1. Field of the Invention
The present invention relates to an adhesive sheet. More specifically, the present invention relates to an adhesive sheet used in manufacturing processes of electronic components, for dicing and/or conveying.
2. Description of the Related Art
A semiconductor wafer is generally fed, after being provided with circuits and then being attached with an adhesive sheet, to processes such as dividing into small pieces of elements (dicing), cleaning, drying, stretching the adhesive sheet (expanding), exfoliating the small pieces of elements from the adhesive sheet (picking up), and mounting. Patent Document 1 describes a substrate in which polyvinyl chloride is used, as an example of an adhesive sheet for dicing and/or conveying, used in these processes.
Further, in relation to the present invention, Patent Document 2 describes, as an adhesive composition, a composition in which two types of (meth) acrylate copolymers differing in weight-average molecular weight are used.
Further, Patent Document 3 describes a technique employing a polyester-based plasticizer in order to prevent loss of adhesive force with time in an adhesive sheet as a skin patch.